SOCS family proteins form part of a classical negative feedback system that regulates cytokine signal transduction. Substrate- recognition component of a SCF-like ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Inhibits EGF signaling by mediating the degradation of the Tyr-phosphorylated EGF receptor/EGFR. {ECO:0000269|PubMed:15590694, ECO:0000269|PubMed:17997974}. This is the function of SOCS4 (suppressor of cytokine signaling 4, ENSG00000180008).